Sailboat hydrolized hull repair

"Marco" <marco59.TakeThisOut@hotmail.com> wrote in message
news:1145465268.562627.188070@i40g2000cwc.googlegroups.com...
<...>
> Working with epoxy, I would like to here from us some opinions about
> differents approch:
>
> 1) Add two or three layer of 300 gr/sqmt biassial 45-/-45,but I know
> the difficult
> or the impossibility to work "overhead" due to the cloth weight.

I've re-cored deck section from underneath with a heavy "roving" - that
thick real corse weave stuff. 24 oz/square yard - I'll let you do the
conversion.

I used a "general purpose" epoxy (West Systems 105/205 ) - it took some
effort to get the cloth in place, but once it was up overhead, it stayed in
place on it's own. I would think that a "laminating resin" would not be as
sticky and would not work as well overhead.

My suggestion is to buy a small quantity of the cloth and experiment with it
to be sure it will work for you. If it sticks to the hull without too much
effort, you are ready to get the job done. If not, you won't have any
problem getting it off, and you can try something else.

>
> 2) Use more layers of lighter glass cloth (150 gr/sqmt).would it be an
> easier job?
>
Don't know.

> 3) vacuum bagging, but... is it possible to do it "overhead" ? How?

Possible, sure. Necessary, I doubt it.
>
> 4) dismanting,remove the keel,engine etc.etc. and flip the boat but I
> have to do a lot of

I don't think this is at all necessary.

> Last,I have to work in outdoor enviroment.

Don't we all?

--
Geoff
The Sea Hawk at Wow Way d0t Com
remove spaces and make the obvious substitutions to reply by mail
When immigration is outlawed, only outlaws will immigrate.
 >> Stay informed about: Sailboat hydrolized hull repair 

Marco wrote:
> Hi all from Italy...
> due to severe hydrolysis of all the originally low saturated external
> mat of my 27" sailboat, I went to "scrape" it off by hands with chisel
> (a very hard job!!)
> I mostly removed all the mat until the first layer of cloth.
> The hull is stucturally countermoulded,so the the hull itself is not
> very thick,and it needs to be relaminated to the original thickness.
> Asked around boatyards,skilled DIY,experts,everyone has the "right" and
> valid solution )
> I discarded polyester or vinilester due to poor adesion.
> Working with epoxy, I would like to here from us some opinions about
> differents approch:
>
> 1) Add two or three layer of 300 gr/sqmt biassial 45-/-45,but I know
> the difficult
> or the impossibility to work "overhead" due to the cloth weight.
>
> 2) Use more layers of lighter glass cloth (150 gr/sqmt).would it be an
> easier job?
>
> 3) vacuum bagging, but... is it possible to do it "overhead" ? How?
>
> 4) dismanting,remove the keel,engine etc.etc. and flip the boat but I
> have to do a lot of
> work and not sure if the boatyards will cooperate,as they never
> done it before.
>
> Last,I have to work in outdoor enviroment.
>
> Thanks for any suggestion.
> Ciao from Roma,Italy
> Marco
>

It is not impossible to work overhead with moderate sizes of 300 gm
biaxial. I've done it a fair bit on my current project.

A few tricks:

- wet out cloth on a plastic coated horizontal table with resin

- sprinkle with some colloidal silica (not very much, like dusting a
cake with icing sugar is my best description). This makes the resin
thicker and it will not run down the cloth before it sets. It also
sticks better to the hull

- squeegee the silica into the resin until it is absorbed

- leave top edge of cloth with no resin in it (say 50mm minimum)

- apply strong & wide duct or masking tape to top edge of cloth

- roll cloth onto PVC pipe

- take to hull, tape top edge in place, and carefully unroll,
squeegeeing as you go

- you NEED a helper for this job, especially if you use 50" wide cloth

- after resin cures, trim off edge where the cloth has no resin, sand
smooth

Good luck. It is an ugly job but it is possible. Wash the hull down
with lots of fresh water and solvent like xylene. Then I would also
make sure the hull is covered with plastic and a dehumidifier is used
for a few weeks before starting.

Evan Gatehouse
 >> Stay informed about: Sailboat hydrolized hull repair 

"Evan Gatehouse" wrote:

> It is not impossible to work overhead with moderate sizes of 300 gm
> biaxial. I've done it a fair bit on my current project.
>
> A few tricks:
>
> - wet out cloth on a plastic coated horizontal table with resin

You mean plastic film to be rolled on pvc pipe together with cloth to help
the unrolling?

> CUT...

> Good luck. It is an ugly job but it is possible. Wash the hull down
> with lots of fresh water and solvent like xylene. Then I would also
> make sure the hull is covered with plastic and a dehumidifier is used
> for a few weeks before starting.

The dehumidifier is already running...

Thanks to everybody for the suggestions, I would thinking to wet the hull
with plain
epoxy and wait until it becomes sticky. Do you believe it will be useful or
not?

Marco
 >> Stay informed about: Sailboat hydrolized hull repair 

Marco wrote:
> "Evan Gatehouse" wrote:
>
>
>>It is not impossible to work overhead with moderate sizes of 300 gm
>>biaxial. I've done it a fair bit on my current project.
>>
>>A few tricks:
>>
>>- wet out cloth on a plastic coated horizontal table with resin
>
>
> You mean plastic film to be rolled on pvc pipe together with cloth to help
> the unrolling?
>

No. Cover a table with polyethylene plastic to provide a surface that
is smooth and doesn't absorb extra resin. Any extra resin gets
absorbed by the next batch of cloth. Table can be a piece of plywood
on sawhorses next to the hull.

>
>> CUT...
>
>
>>Good luck. It is an ugly job but it is possible. Wash the hull down
>>with lots of fresh water and solvent like xylene. Then I would also
>>make sure the hull is covered with plastic and a dehumidifier is used
>>for a few weeks before starting.
>
>
> The dehumidifier is already running...
>
> Thanks to everybody for the suggestions, I would thinking to wet the hull
> with plain
> epoxy and wait until it becomes sticky. Do you believe it will be useful or
> not?

Yes, but it becomes a bit of a challenge to get on the cloth before
the epoxy passes into the gel stage. In other words, you can roll
lots of epoxy onto the hull easily but it takes significant time to
wet out the cloth and apply it. I wouldn't try to do the whole hull
in one day.

> Marco
>
>
>
 >> Stay informed about: Sailboat hydrolized hull repair 

Lay out the roving/mat/whatever on sturdy polyethylene sheet.
Wet out the glass, and lift into place.

It's not as easy as it sounds.


Richard
 >> Stay informed about: Sailboat hydrolized hull repair